Manufacturing method of original plate and semiconductor device

ABSTRACT

According to one embodiment, an original plate for imprint lithography has a first surface side having a patterned portion thereon. The patterned portion includes a groove having a bottom surface recessed from a first surface to a first depth, and a columnar portion on the bottom surface and protruding from the bottom surface to extend beyond the first surface. The original plate may be used to form replica templates by imprint lithography processes. The replica templates can be used in semiconductor device manufacturing processes or the like.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.17/187,696, filed on Feb. 26, 2021, which is based upon and claims thebenefit of priority from Japanese Patent Application No. 2020-043814,filed on Mar. 13, 2020, the entire contents of each of which areincorporated herein by reference.

FIELD

Embodiments described herein relate generally to a method ofmanufacturing an original plate, such as an imprint template or mold,and a semiconductor device.

BACKGROUND

In the manufacturing process of a semiconductor device, the dualdamascene method may be used in which a via connected to a lower layerstructure and an upper layer wiring connected to the via are formedtogether. In addition, an imprint method may be applied to the formationof the via and the upper layer wiring for the dual damascene method. Inan imprint method, a resist is formed on a film-to-be-processed, then atemplate on which a pattern has been formed is pressed against theresist to pattern the resist. The pattern of the template is transferredto the resist. However, in some cases, if holes that are to become viasand grooves that are to become the upper layer wiring are collectivelytransferred to the resist in a single process, the desired shape cannotbe obtained in the to-be-process film due to insufficient etch selectionratio of the imprinted resist, or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C are diagrams showing an example of the configuration of areplica template according to an embodiment.

FIGS. 2A to 2D are cross-sectional views depicting aspects of asemiconductor device manufacturing method according to an embodiment.

FIGS. 3A to 3C are cross-sectional views depicting aspects of asemiconductor device manufacturing method according to an embodiment.

FIGS. 4A to 4F are cross-sectional views depicting aspects of asemiconductor device manufacturing method according to an embodiment.

FIGS. 5A to 5F are cross-sectional views depicting aspects of asemiconductor device manufacturing method according to an embodiment.

FIG. 6 is cross-sectional view depicting aspects of a semiconductordevice manufacturing method according to an embodiment.

FIGS. 7A to 7C are diagrams showing an example of the configuration of amaster template according to an embodiment.

FIGS. 8A to 8F are cross-sectional views depicting aspects of a mastertemplate manufacturing method according to an embodiment.

FIGS. 9A to 9D are cross-sectional views depicting aspects of a mastertemplate manufacturing method according to an embodiment.

FIGS. 10A to 10C are cross-sectional views depicting aspects of a mastertemplate manufacturing method according to an embodiment.

FIGS. 11A to 11F are cross-sectional views depicting aspects of a mastertemplate manufacturing method according to an embodiment.

FIGS. 12A and 12B are cross-sectional views depicting aspects of amaster template manufacturing method according to an embodiment.

FIGS. 13A to 13F are cross-sectional views showing an example of aprocedure of a semiconductor device manufacturing method of according toa comparative example.

FIGS. 14A to 14C are cross-sectional views showing an example of aprocedure of a semiconductor device manufacturing method according tothe comparative example.

DETAILED DESCRIPTION

Embodiments provide a manufacturing method for an original plate and asemiconductor device, which facilitates obtaining desired shapes in afilm-to-be-processed.

In general, according to one embodiment, an original plate for imprintlithography has a first surface side having a patterned portion thereon.The patterned portion includes a groove having a bottom surface recessedfrom a first surface to a first depth, and a columnar portion on thebottom surface and protruding from the bottom surface to extend beyondthe first surface.

Hereinafter, the present disclosure will be described in with referenceto the drawings. The present disclosure is not limited to the followingexample embodiments. In addition, the components in the followingembodiments include those that can be easily conceived by those skilledin the art or those that are substantially the same.

[Structure of Replica Template]

FIGS. 1A to 1C are diagrams showing an example of the configuration of areplica template 10 according to an embodiment. FIG. 1A is across-sectional view, FIG. 1B is a partially enlarged cross-sectionalview, and FIG. 1C is a partial perspective view.

The replica template 10 is a template (mold) for imprinting. A pattern10 p is in the replica template 10. This pattern 10 p is transferred toa resist film disposed on a film-to-be-processed. Thefilm-to-be-processed can be a part of the final semiconductor deviceproduct or the like. The replica template 10 is mass-produced from amaster template. The master template has a topographic pattern which isthe inverse of the pattern 10 p in the replica template 10.

In the present specification, the direction in which the surfaces havingthe patterns of the replica template 10 and the master template face isreferred to as upward, and the opposite direction is referred to asdownward. Therefore, in the present specification, in the configurationshaving respective patterns of the replica template 10 and the mastertemplate, there may be cases where the distance from a predeterminedposition to a certain position above is referred to as height and thedistance from a predetermined position to a certain position below isreferred to as depth.

As shown in FIG. 1A, the replica template 10 includes a base material 10b made of a transparent material such as glass or quartz. The basematerial 10 b has, for example, a rectangular planar shape. On a mainsurface 10 s of the base material 10 b, a mesa portion 10 m protrudingfrom the main surface 10 s is disposed. The mesa portion 10 m isdisposed in the center of the base material 10 b, for example. The othermain surface 10 e of the base material 10 b is provided with acounterbore 10 c in which a part of the base material 10 b is removedfrom the main surface 10 e side.

The pattern 10 p is disposed on the upper surface of the mesa portion 10m. The pattern 10 p has, for example, a periodic structure in which apredetermined unit structure 10 u is periodically repeated. FIGS. 1B and1C are extracted unit structures 10 u of the pattern 10 p depicted inFIG. 1A.

As shown in FIGS. 1B and 1C, the unit structure 10 u of the pattern 10 pis disposed on a basal plane 11 as a first surface of the mesa portion10 m. The unit structure 10 u includes, for example, a step portion 12protruding from the basal plane 11 at a predetermined height, and a hole13 disposed in the step portion 12.

The step portion 12 extends in a predetermined direction along the basalplane 11, for example, and has an upper surface 12 t and side surfaces12 w. The upper surface 12 t which is the upper step surface of the stepportion 12 has, for example, a rectangular shape and has a substantiallyflat surface. The respective side surfaces 12 w are disposed on theouter sides, in the width direction, of the upper surface 12 t. Thewidth direction in this context is a direction intersecting theextending direction of the step portion 12. Each side surface 12 wextends from the upper surface 12 t to the basal plane 11. The two sidesurfaces 12 w are substantially parallel to each other in the extendingdirection of the step portion 12. However, the step portion 12 may havea tapered shape with the distance between the two side surfaces 12 wincreased from the upper surface 12 t of the step portion 12 toward thebasal plane 11.

As will be described further, the shape of the step portion 12 istransferred to the film-to-be-processed, which becomes, for example, anupper layer wiring in the semiconductor device. Therefore, the stepportion 12 may bend in various directions and/or may extend in a curvedshape or a serpentine shape, instead of extending in just one directionor in a straight line as described above.

The hole 13 has an opening 13 t at the upper surface 12 t of the stepportion 12 and extends to a predetermined depth into the mesa portion 10m of the base material 10 b. The hole 13 has a substantially flat bottomsurface 13 ba. The depth from the opening 13 t to the bottom surface 13b is larger than, for example, the height of the step portion 12 fromthe basal plane 11. Therefore, the bottom surface 13 b of the hole 13 islocated at a position deeper than the basal plane 11 in this example.

The shape of the hole 13 is also transferred to the film-to-be-processedand ultimately becomes a via connecting the upper layer wiring to alower layer structure, for example. Therefore, it is desirable that thecross section of the hole 13 orthogonal to the depth direction has arounded shape such as a circular shape, an elliptical shape, or an ovalshape. That is, the cross-section shape of the hole preferably has nocorners. Further, the hole 13 may have a tapered shape with the diameterat the opening 13 t being larger than the diameter at the bottom surface13 b.

[Manufacturing Method of Semiconductor Device]

Next, a manufacturing method of a semiconductor device 200 of theembodiment will be described with reference to FIGS. 2A to 6 . FIGS. 2Ato 6 are cross-sectional views showing an example of a procedure of amanufacturing method of the semiconductor device 200 according to theembodiment. In the manufacturing method of the semiconductor device 200,the replica template 10 is used and a dual damascene method, in which avia 223 v and an upper layer wiring 222 w (see FIG. 6 ) are collectivelyformed on an insulating film 220, is applied.

In this specification, the vertical direction in description of thesemiconductor device 200 is set based on the via 223 v and the upperlayer wiring 222 w. That is, the via 223 v is assumed to be locatedbelow the upper layer wiring 222 w and the upper layer wiring 222 w isassumed to be located above the via 223 v. The lower layer structure islocated further below the via 223 v and the upper layer wiring 222 w.Furthermore, when the terms “above” and “below” are used, it does notnecessarily mean that components having the stated vertical relationshipare in contact with each other.

FIGS. 2A to 2D show how a transistor TR corresponding to a lower layerstructure connected to the via 223 v is formed.

As shown in FIG. 2A, a gate electrode GE is formed on a semiconductorsubstrate 210 (“substrate 210”) such as a silicon substrate. As shown inFIG. 2B, a sidewall spacer SW covering the gate electrode GE is formed.As shown in FIG. 2C, source and drain SDs are formed on the surfacelayer of the substrate 210 on both sides of the gate electrode GE, forexample, by a self-alignment process.

As described above, the transistor TR including the gate electrode GEand the source and drain SD is formed. However, the method for formingthe transistor TR is not limited to the above, and various methods maybe used.

As shown in FIG. 2D, the transistor TR is then covered with theinsulating film 220, such as a silicon oxide film formed from tetraethylorthosilicate (TEOS) or the like. A carbon film 230 (e.g., carbon-basedfilm formed from a spin-on-carbon (SOC) material or the like) is formedon the insulating film 220.

Next, the replica template 10 is used in an imprint lithography process.FIGS. 3A to 3C show how the unit structure 10 u of the pattern 10 p inthe replica template 10 is pressed against a resist film 240 formed onthe carbon film 230.

As shown in FIG. 3A, the resist film 240 is formed on the carbon film230 above the substrate 210. The pattern 10 p of the replica template 10having the step portion 12, the hole 13, and the like is placed inproximity to the resist film 240.

The resist film 240 may be, for example, a photocurable resist that iscured by light, a thermosetting resist that is cured by heating, or thelike. Further, the resist film 240 can be formed by dispensing theresist as droplets onto a shot region, which is the region processed ineach imprint process, or by applying the resist to the entire substrate210 by spin coating or the like.

As shown in FIG. 3B, the pattern 10 p of the replica template 10 ispressed against the resist film 240. Then, in this state, if the resistfilm 240 is a photocurable resist, it is irradiated with light, or ifthe resist film 240 is a thermosetting resist, it is heated to cure theresist film 240.

When the replica template 10 is pressed against the resist film 240, aslight distance from the lower carbon film 230 is maintained in order toprevent the replica template 10 from contact with the substrate 210 andthe like, which might damage the replica template.

As shown in FIG. 3C, the replica template 10 is released after theresist film 240 is cured. The resist film 240 becomes a resist pattern240 p to which the pattern 10 p of the replica template 10 has beentransferred.

The resist pattern 240 p includes a groove 242 corresponding to the stepportion 12 of the replica template 10 and a pillar 243 corresponding tothe hole 13. The groove 242 has a shape recessed in the film thicknessdirection of the resist pattern 240 p, and the pillar 243 has a shapeprotruding from the bottom surface of the groove 242. The resist pattern240 p has a pattern in which the topographic pattern of the pattern 10 pof the replica template 10 has been inverted.

Since the replica template 10 is pressed against the resist film 240with a slight distance from the carbon film 230 maintained, the resistpattern 240 p includes a slight residual resist film 240 r at the bottomsurface of the groove 242.

Next, the pattern is sequentially transferred from the resist pattern240 p to the carbon film 230 and the insulating film 220. The relatedprocessing is shown in FIGS. 4A to 4F and 5A to 5F.

FIG. 4A shows the state after the imprint process shown in FIG. 3C.

As shown in FIG. 4B, the resist pattern 240 p is etched to remove theresist residual film 240 r.

As shown in FIG. 4C, the carbon film 230 is then partially etched. As aresult, a portion of the carbon film 230 below the now-removed resistresidual film 240 r is etched to form a carbon film pattern 230 pincluding a shallow groove 232 h recessed to a predetermined depth inthe film thickness direction of the carbon film 230 and a protrusion 233p disposed in the shallow groove 232 h.

The resist pattern 240 p and the carbon film 230 are made of similarmaterials, each containing a large amount of carbon. Therefore, forexample, the carbon film 230 can be etched in the same removal processof the resist residual film 240 r shown in FIG. 4B, that is, under thesame etching conditions or similar etching conditions.

Further, in the process of FIG. 4C, the carbon film 230 wasapproximately half-etched to form the shallow groove 232 h, but at thisstage, in other examples, a through groove entirely penetrating thecarbon film 230 in the film thickness direction may be formed instead.

As shown in FIG. 4D, an inverted film 250 is formed covering the resistpattern 240 p and the carbon film pattern 230 p exposed from the resistpattern 240 p. The inverted film 250 is made of a non-carbon materialdifferent from the resist pattern 240 p and the carbon film pattern 230p, and is, for example, an oxide film such as a silicon oxide filmformed from a spin-on-glass (SOG) material.

By only partially etching through the carbon film 230 and leaving a partthereof remaining, the height difference of the uneven portion of theresist pattern 240 p and the carbon film pattern 230 p can be reduced,and the inverted film 250 can be more easily formed to have a flat uppersurface.

As shown in FIG. 4E, the inverted film 250 is etched back to expose apart of the pillar 243 of the resist pattern 240 p at the upper surfaceof the inverted film 250. At this time, the amount of the pillar 243exposed can be adjusted as appropriate. It is generally sufficient if atleast the top (uppermost surface) of the pillar 243 is exposed from theupper surface of the inverted film 250.

Since the inverted film 250 is made of a non-carbon material differentfrom the resist pattern 240 p, the selection ratio (etch selectively)with respect to the resist pattern 240 p can be increased, the invertedfilm 250 can be selectively etched to expose the pillar 243 of theresist pattern 240 p without substantial removal of the pillar 243material.

As shown in FIG. 4F, next the pillar 243 previously exposed from theupper surface of the inverted film 250 is removed. At this time, it ispossible to set processing conditions for selectively etching the pillar243 of the resist pattern 240 p with respect to the inverted film 250 byutilizing the material differences between the inverted film 250 and theresist pattern 240 p.

As a result, an inverted film pattern 250 p having a hole 253 isgenerated by removing the pillar 243. The hole 253 opens on theprotrusion 233 p of the carbon film pattern 230 p.

As shown in FIG. 5A, the protrusion 233 p is removed by etching throughthe hole 253 of the inverted film pattern 250 p. Also at this time, thecarbon film pattern 230 p can be selectively etched while ensuring theselection ratio of the inverted film pattern 250 p by utilizing thematerial difference between the inverted film pattern 250 p and thecarbon film pattern 230 p.

As a result, a hole 233 that opens at the bottom surface of the shallowgroove 232 h of the carbon film pattern 230 p is formed.

That is, by the processes up to this point, the pillar 243 formed in thegroove 242 of the resist pattern 240 p has been turned into the hole 233penetrating the inside of the carbon film pattern 230 p in the depthdirection. As described above, the inverted film 250 has a function ofinverting the pattern of the resist pattern 240 p.

As shown in FIG. 5B, the insulating film 220 is etched through the hole253 of the inverted film pattern 250 p and the hole 233 of the carbonfilm pattern 230 p. In the example of the present embodiment, theinverted film pattern 250 p and the insulating film 220 are bothsilicon-based oxide films and are made of similar materials. Therefore,it is generally difficult to secure etch selectivity between theinverted film pattern 250 p and the insulating film 220. However, byappropriately setting the film thickness of the inverted film 250 thatis formed, the film thickness of the inverted film pattern 250 p can besufficiently maintained until the etching of the insulating film 220 iscompleted.

As a result, a through via hole 223 t is formed in the insulating film220. The through via hole 223 t penetrates the insulating film 220 andreaches, for example, the source and drain SD of the transistor TRformed on the substrate 210.

As shown in FIG. 5C, the remaining inverted film pattern 250 p can beselectively etched and removed while ensuring an appropriate selectionratio with the resist pattern 240 p.

As shown in FIG. 5D, the shallow groove 232 h of the carbon film pattern230 p is additionally etched to form a through groove 232 in the carbonfilm pattern 230 p. At this time, the carbon film pattern 230 p isselectively etched while ensuring a selection ratio with the insulatingfilm 220.

The opening of the through via hole 223 t is exposed at the bottomsurface of the through groove 232. As described above, by ensuring theselection ratio between the insulating film 220 and the carbon filmpattern 230 p, etching of the edge portion of the opening of the throughvia hole 223 t is prevented. The edge portion of the opening of thethrough via hole 223 t may be referred to as a shoulder portion, a rimof the opening, an upper edge of the opening, or the like. The shape ofthe bottom surface of the through groove 232 can be adjusted so that theshape of the bottom surface of the through groove 232 of the carbon filmpattern 230 p becomes flat.

As shown in FIG. 5E, the insulating film 220 is etched using the resistpattern 240 p and the carbon film pattern 230 p as masks. In thisprocess, it is difficult to secure a selection ratio between the resistpattern 240 p and the carbon film pattern 230 p. However, even if theresist pattern 240 p is removed completely, it can still be sufficientif the carbon film pattern 230 p (or some portion thereof) remains untilthe etching of the insulating film 220 is completed.

By the above etching, a wiring groove 222 having a predetermined depthis formed on the upper portion of the insulating film 220. As a result,the upper portion of the through via hole 223 t of the insulating film220 is removed, and a via hole 223 to which the wiring groove 222 isconnected is formed. Since the carbon film pattern 230 p remains untilthe etching is completed, the edge portion of the opening of the wiringgroove 222, that is, the shoulder opening of the wiring groove 222remains protected.

As shown in FIG. 5F, the carbon film pattern 230 p is removed by etchingwhile ensuring the selection ratio with the insulating film 220.

As described above, the via hole 223 to which the wiring groove 222 isconnected can be collectively formed in the insulating film 220 from aresist pattern 240 p in which the pillar 243 protrudes from the bottomsurface of the groove 242.

After that, the via hole 223 and the wiring groove 222 of the insulatingfilm 220 are filled with a metal material such as tungsten or copper.FIG. 6 depicts the process.

As shown in FIG. 6 , the semiconductor device 200 of the embodiment ismanufactured by an imprint method using the replica template 10 and adual damascene method using the resist pattern 240 p pattern created bythe imprint method.

The semiconductor device 200 includes the transistor TR, the via 223 v,and the upper layer wiring 222 w. A substrate 210 may be provided in thesemiconductor device 200. As described above, the transistor TR isdisposed on the substrate 210. The lower end of the via 223 v isconnected to the source and drain SD of the transistor TR. The upper endof the via 223 v is connected to the upper layer wiring 222 w. The via223 v and the upper layer wiring 222 w have a metal material 224 filledin the via hole 223 and the wiring groove 222 described above. As aresult, the source and drain SD of the transistor TR and the upper layerwiring 222 w are electrically connected.

In the processing examples shown in FIGS. 2A to 6 , the via 223 v andthe upper layer wiring 222 w connected to the source and drain SD of thetransistor TR are formed. However, the manufacturing method of thesemiconductor device 200 of the embodiment can also be applied to, forexample, the case of forming a via and an upper layer wiring connectedto the gate GE of the transistor TR.

Further, in the processing examples shown in FIGS. 2A to 6 , the lowerlayer structure is a transistor TR. However, the manufacturing method ofthe semiconductor device 200 can also be applied to the case of forminga via and an (upper layer) wiring connected to, for example, the upperlayer wiring 222 w or a wiring further above the upper layer wiring 222w.

Further, in the process example shown in FIGS. 2A to 6 , thesemiconductor device 200 is disposed on the substrate 210. However, thesemiconductor device may be disposed on a substrate other than asemiconductor substrate, such as, for example, a ceramic substrate, aglass substrate, or a quartz substrate.

[Structure of Master Template]

Next, the configuration of a master template 20 of the embodiment willbe described with reference to FIGS. 7A to 7C. FIGS. 7A to 7C arediagrams showing an example of the configuration of the master template20 according to an embodiment. FIG. 7A is a cross-sectional view, FIG.7B is a partially enlarged cross-sectional view, and FIG. 7C is apartial perspective view.

The master template 20 is a template for imprinting. The master template20 may be referred to as an original plate, an original mold, a master,a master mold, or the like. Th master template 30 has a pattern 20 pthat can be transferred to a resist film on a template blank or the liketo be processed into a replica template 10. A plurality of replicatemplate 10 can be produced from a single master template 20.

As shown in FIG. 7A, the master template 20 includes a base material 20b made of a transparent material such as glass or quartz. On a mainsurface 20 s of the base material 20 b, a mesa portion 20 m protrudingfrom the main surface 20 s is disposed. The mesa portion 20 m isdisposed in the center of the base material 20 b, for example. The othermain surface 20 e of the base material 20 b is provided with acounterbore 20 c in which a part of the base material 20 b is removedfrom the other main surface 20 e side.

The pattern 20 p is disposed on the upper surface of the mesa portion 20m. The pattern 20 p has, for example, a periodic structure in which apredetermined unit structure 20 u is periodically repeated. FIGS. 7B and7C depict extracted unit structures 20 u of the pattern 20 p in FIG. 7A.

As shown in FIGS. 7B and 7C, the unit structure 20 u of the pattern 20 pis disposed on a basal plane 21 of the mesa portion 20 m. The unitstructure 20 u includes, for example, a groove 22 having a bottomportion recessed from the basal plane 21 to a predetermined depth, and apillar 23 disposed at the bottom portion of the groove 22.

The groove 22 extends in a predetermined direction along the basal plane21, and has a bottom surface 22 b and side surfaces 22 w. The bottomsurface 22 b is, for example, rectangular and has a substantially flatsurface. Each side surface 22 w extends from the bottom surface 22 b tothe basal plane 21. The two side surfaces 22 w are substantiallyparallel to each other in the extending direction. However, the groove22 may have a tapered shape with the distance between the two sidesurfaces 22 w increased from the bottom surface 22 b toward the basalplane 21.

The groove 22 may be bent or angle in various directions and may extendin a curved shape or a serpentine shape, instead of extending in just asingle direction or in a straight line.

The pillar 23 has a base portion 23 b on the bottom surface 22 b of thegroove 22 and extends from the bottom surface 22 b to a predeterminedheight. The pillar 23 has a substantially flat upper surface 23 t at thetop. The height of the pillar 23 from the base portion 23 b to the uppersurface 23 t is larger than the depth of the groove 22 from the basalplane 21. Therefore, the upper surface 23 t of the pillar 23 is locatedhigher than the basal plane 21 and protrudes from the basal plane 21.

It is desirable that the cross section of the pillar 23 orthogonal tothe height direction has a rounded shape such as a circular shape, anelliptical shape, or an oval shape, that is, a shape having no corners.Further, the pillar 23 may have a tapered shape with the diameter of thebase portion 23 b being larger than the diameter of the pillar 23 at theupper surface 23 t.

[Manufacturing Method of Master Template]

Next, a manufacturing method of the master template 20 of the presentembodiment will be described with reference to FIGS. 8A to 8F and 9A to9D. FIGS. 8A to 8F and 9A to 9D are cross-sectional views showing anexample of the procedure of the manufacturing method of the mastertemplate 20 according to the embodiment.

As shown in FIG. 8A, a hard mask (HM) film 30, which is a filmcontaining a metal such as chromium, molybdenum, tantalum, or the like,or carbon is formed on the base material 20 b made of glass, quartz, orthe like in a flat shape. At this time, in consideration of thesubsequent processes, the HM film 30 is made thicker than mightotherwise be usual. Next, a resist film 40, which in this example is aresin film suitable for electron beam (EB) drawing (patterning), isformed on the HM film 30.

As shown in FIG. 8B, the resist film 40 is processed by EB drawing toform a pillar 43 composed of the resist film 40.

As shown in FIG. 8C, the HM film 30 is etched using the pillar 43 as amask to form a pillar 33 composed of the HM film 30. As a result, thesurface of the base material 20 b is exposed except for the portionwhere the pillars 43 and 33 are formed.

As shown in FIG. 8D, the exposed surface of the base material 20 b isetched using the pillar 33 as a mask. As a result, the surface of thebase material 20 b is removed by a predetermined thickness, and the basematerial 20 b has an etched surface. This etched surface becomes thebasal plane 21 of the master template 20.

As a result, a protrusion 23 p protruding from the basal plane 21 of thebase material 20 b is formed. At this time, the pillar 43 may beremoved. However, since the HM film 30 was thick, a part of the pillar33 still remains. In other words, the thickness of the HM film 30 is setin the processing of FIG. 8A so that at least a part of the pillar 33remains after the processing of FIG. 8D.

As shown in FIG. 8E, a material comprising a metal, such as chromium,molybdenum, tantalum, or carbon is sputtered onto the base material 20 bincluding the pillar 33 of the protrusion 23 p. As a result, an HM film50 having a predetermined thickness is formed on the basal plane 21 ofthe base material 20 b and a pillar 53 composed of the sputtered (orotherwise deposited) material is formed on the pillar 33. As a result,an HM pattern 50 p having the HM film 50 and the pillars 33 and 53 areformed.

Here, the material member sputtered on the base material 20 b may be,for example, the same material as the material constituting the HM film30, or may be a different material. Further, the characteristics of theHM film 30 and the HM pattern 50 p, such as etching resistance, may bedifferent. When the HM film 30 and the HM pattern 50 p are made of thesame material, the characteristics of the two can be made different by,for example, different sputtering conditions. When the HM film 30 andthe HM pattern 50 p are different materials, the characteristics of thetwo can be made different by selecting the respective materials.

For etching the base material 20 b, it is preferable that the etchingresistance of the HM film 30 is higher than the etching resistance ofthe HM pattern 50 p. In other words, the pillar 33 composed of the HMfilm 30 is required to have higher etching resistance.

As shown in FIG. 8F, a resist film 60 is formed to cover the entire HMpattern 50 p. The resist film 60 is a resin film suitable for EBdrawing.

As shown in FIG. 9A, the resist film 60 is processed by EB drawing toform a resist pattern 60 p having a through groove 62 reaching the HMpattern 50 p. As a result, a part of the HM film 50 of the HM pattern 50p and all of the pillar 33 and the pillar 53 are exposed.

As shown in FIG. 9B, the HM pattern 50 p is etched using the resistpattern 60 p as a mask. As a result, a part of the HM film 50 of the HMpattern 50 p is removed and a part of the basal plane 21 of the basematerial 20 b is exposed. Further, since the pillar 53 of the HM pattern50 p is removed so as to have a film thickness substantially equal tothat of the HM film 50 and the upper surface of the pillar 33 isexposed.

As shown in FIG. 9C, the base material 20 b is etched using the resistpattern 60 p and the HM pattern 50 p as masks. As a result, the groove22 recessed from the basal plane 21 to a predetermined depth is formedin the base material 20 b. As a result, the pillar 23 having the baseportion 23 b is formed on the bottom surface 22 b of the groove 22. Atthis time, at least a part of the pillar 33 of the HM pattern 50 premains and the upper surface 23 t of the pillar 23 is protected untilthe etching is completed.

As shown in FIG. 9D, the resist pattern 60 p and the HM pattern 50 p areremoved.

[Manufacturing Method of Replica Template]

Next, a method of manufacturing the replica template 10 of theembodiment will be described with reference to FIGS. 10A to 12B. FIGS.10A to 12B are cross-sectional views showing an example of the procedureof the manufacturing method of the replica template 10 according to theembodiment.

As shown in FIG. 10A, an HM film 130, which is a film containing a metalsuch as chromium, molybdenum, tantalum, or the like, or carbon, isformed on the base material 10 b, which is made of glass, quartz, or thelike. A photocurable or thermosetting resist film 140 is formed on theHM film 130.

The HM film 130 does not have to be particularly thick in this process.The resist film 140 can be locally dispensed onto each shot region ofthe base material 10 b or applied to the entire base material 10 b byspin coating or the like.

The resist film 140 formed on the base material 10 b is brought intoproximity with the pattern 20 p of the master template 20 having thegroove 22, the pillar 23, and the like.

As shown in FIG. 10B, the pattern 20 p of the master template 20 ispressed against the resist film 140. Then, in this state, the resistfilm 140 is irradiated with light, or the resist film 140 is heated tocure the resist film 140.

As shown in FIG. 10C, the master template 20 is released after theresist film 140 is cured. The resist film 140 becomes a resist pattern140 p to which the pattern 20 p of the master template 20 has beentransferred.

The resist pattern 140 p has a step portion 142 to which the groove 22of the master template 20 corresponds, and a hole 143 to which thepillar 23 of the master template 20 corresponds. The step portion 142protrudes from the upper surface of the resist pattern 140 p, and thehole 143 has a shape recessed from the upper surface of the step portion142 in the film thickness direction of the resist pattern 140 p. Theresist pattern 140 p includes a resist residual film 140 r at the bottomof the hole 143.

FIG. 11A shows the state after the imprint process shown in FIG. 10C.

As shown in FIG. 11B, the resist pattern 140 p is etched to remove theresist residual film 140 r.

As shown in FIG. 11C, the HM film 130 is etched using the resist pattern140 p as a mask. As a result, an HM pattern 130 p is formed through theportion of the resist pattern 140 p corresponding to the hole 143.

As shown in FIG. 11D, etching with the resist pattern 140 p as a mask iscontinued and the base material 10 b exposed from the penetratingportion of the HM pattern 130 p is etched. As a result, a shallow hole13 h is formed in the base material 10 b. The shallow hole 13 h is aconfiguration corresponding to the hole 13 of the replica template 10and is a hole shallower than the hole 13. The shallow hole 13 h is laterfurther etched to become the hole 13 having a predetermined depth.

As shown in FIG. 11E, the resist pattern 140 p is etched back. As aresult, the step portion 142 having the hole 143 of the resist pattern140 p remains on the HM pattern 130 p.

As shown in FIG. 11F, the HM pattern 130 p is etched using the stepportion 142 of the resist pattern 140 p as a mask. As a result, the stepportion 142 of the resist pattern 140 p and the HM pattern 130 p belowthe step portion 142 remain on the base material 10 b.

As shown in FIG. 12A, the base material 10 b is etched using the stepportion 142 of the resist pattern 140 p and the HM pattern 130 p belowthe step portion 142 as masks. As a result, the surface of the basematerial 10 b is removed by a predetermined thickness, and the basematerial 10 b has an etched surface. This etched surface becomes thebasal plane 11 of the replica template 10.

The base material 10 b below the HM pattern 130 p protrudes from theetched surface of the base material 10 b. That is, the basal plane 11and the step portion 12 are formed. Now the shallow hole 13 h is furtheretched to form the hole 13 having a predetermined depth.

As shown in FIG. 12B, the HM pattern 130 p is removed from the uppersurface 12 t of the step portion 12 of the base material 10 b.

Comparative Example

Next, a manufacturing method of a semiconductor device of a comparativeexample will be described with reference to FIGS. 13A to 13F and 14A to14C′.

As shown in FIG. 13A, a replica template 10′ of the comparative examplehas a step portion 12′ and a pillar 13′ protruding on the step portion12′.

An insulating film 220′, a carbon film 230′, and a resist film areformed on a substrate 210′ in this order, and the above replica template10′ is pressed into the resist film to form a resist pattern 240 p′having grooves and holes on the carbon film 230′ (FIG. 13A). The resistresidual film of the resist pattern 240 p′ is removed (FIG. 13B), andthe hole of the resist pattern 240 p′ is transferred to the carbon film230′ to form a carbon film pattern 230 p′ (FIG. 13C). The groove of theresist pattern 240 p′ is transferred to the carbon film pattern 230 p′(FIG. 13D). Next, the hole of the carbon film pattern 230 p′ istransferred to the insulating film 220′ (FIG. 13E), the groove of thecarbon film pattern 230 p′ is transferred to the insulating film 220′,and a via hole 223′ and a wiring groove 222′ are formed (FIG. 13F).

However, the manufacturing method of the semiconductor device of thecomparative example has various problems shown in FIGS. 14A to 14C.

As shown in FIG. 14A, in the process of transferring the groove of theresist pattern 240 p′ to the carbon film pattern 230 p′, the selectionbetween resist pattern 240 p′ and the carbon film 230′ must be low topermit the groove of the resist pattern 240 p′ to be transfer to carbonfilm pattern 230 p′. Therefore, a shoulder opening (upper edge) of thegroove in the resist pattern 240′ will be easily removed in the etching.For example, as shown in FIG. 14A (right page side), a shoulder opening242 s′ of the groove may have a rounded shape, or the width of thegroove may widen from that of the initial resist pattern 240 p′.

As shown in FIG. 14B, in the process of transferring the groove of thecarbon film pattern 230 p′ to the insulating film 220′, the selectionratio between the carbon film pattern 230 p′ and the insulating film220′ must be low to permit the groove of the carbon film pattern 230 p′to transfer to the insulating film 220′. Therefore, a shoulder openingof the hole of the carbon film pattern 230 p′ is easily removed in theetching. For example, as shown in FIG. 14B (right page side), a shoulderopening 233 s′ of the hole may have a rounded shape or the hole diametermay widen from the initial pattern dimension. Furthermore, since thepenetration of the groove of the carbon film pattern 230 p′ and thetransfer to the insulating film 220′ are performed in the same process,it can be difficult to make the depth of the bottom surface of thegroove uniform and the flatness of the bottom surface is likely to beimpaired. Further, the shape of the groove of the resist pattern 240 p′in FIG. 14A (right page side) is transferred to the groove of the carbonfilm pattern 230 p′, and there is nothing to protect a shoulder openingof the groove of the carbon film pattern 230 p′ when the groove istransferred to the insulating film 220′, and a groove shoulder opening232 s′ of the carbon film pattern 230 p′ tends to have a more roundedshape. The width of the groove may thus widen.

As a result, instead of obtaining the ideal shape shown in FIG. 14C(left page side) in the insulating film 220′, for example, a shoulderopening 222 s′ of the wiring groove 222′ and a shoulder opening 223 s′of the via hole 223′ may have a rounded shape as shown in FIG. 14C(right page side). In addition, the dimensional difference between thewiring groove 222′ and the via hole 223′ may become large. Furthermore,the depths of the wiring grooves 222′ are not uniform, and the flatnessof the bottom surface of the wiring grooves 222′ may be impaired.

However, according to the manufacturing method of the semiconductordevice 200, the carbon film 230 and the resist film 240 (which are madeof the same kind of materials) and the inverted film 250 (which is madeof a different material) are used in combination with each other. As aresult, various processes can be performed while appropriately securingan advantageous selection ratio therebetween. Therefore, it becomeseasier to obtain a desired shape in the insulating film 220.

For example, in the process of inverting the pillar 243 of the resistpattern 240 p and transferring the pillar 243 as the hole 233 of thecarbon film pattern 230 p shown in FIG. 5A, the shoulder opening of thegroove 242 of the resist pattern 240 p is protected by the inverted filmpattern 250 p. As a result, the shape of the groove 242 can bemaintained.

Furthermore, the resist pattern 240 p is protected by the inverted filmpattern 250 p during the processes of FIGS. 4D to 5B. Therefore, theprocess of completely transferring the groove 242 of the resist pattern240 p to the carbon film pattern 230 p (as the through groove 232) asshown in FIG. 5D can be performed with the resist pattern 240 p having asufficient film thickness. As a result, the shape of the groove 242 ofthe resist pattern 240 p can be more easily transferred to the throughgroove 232 of the carbon film pattern 230 p with higher accuracy.

According to the manufacturing method of the semiconductor device 200 ofan embodiment, the transfer of the dual damascene shape to theinsulating film 220 is performed stepwise. This also facilitatesobtaining a desired shape in the insulating film 220.

For example, the process of transferring the hole 233 of the carbon filmpattern 230 p to the insulating film 220 shown in FIG. 5B is performedin a state where the entire shoulder opening of the groove 242 and theentire shallow groove 232 h are covered with the inverted film pattern250 p. As a result, the shapes of the groove 242 and the shallow groove232 h can be maintained during the process of transferring the hole 233to the insulating film 220.

Furthermore, the process of transferring the groove 242 to the carbonfilm pattern 230 p shown in FIG. 5D, and the process of transferring thethrough groove 232 to the insulating film 220 shown in FIG. 5E areperformed separately. That is, in the process shown in FIG. 5D, thethrough groove 232 is formed in the carbon film pattern 230 p whileensuring the selection ratio with the insulating film 220, and theinsulating film 220 functions as an etch stop film. As a result, thedepths of the bottom surface 222 b of the wiring groove 222 formed inthe insulating film 220 can be easily aligned and the flatness of thebottom surface 222 b can be easily obtained.

In order to make the bottom surface of the wiring groove uniform andflat, it is conceivable to include a stopper film at a predetermineddepth within the insulating film and use this as the bottom surface ofthe wiring groove. However, this may increase parasitic capacitance(inter-wiring capacitance) of any insulating film including such astopper film. By forming the through groove 232 and the wiring groove222 separately, it becomes easier to obtain the desired shape of thewiring groove 222 without use of an embedded stopper film or the like.

According to the replica template 10 of an embodiment, the step portion12 protruding from the basal plane 11 to a predetermined height and thehole 13 extending from the upper surface 12 t of the step portion 12 toa predetermined depth are provided.

That is, the replica template 10 does not have a shape in which thepillar 13′ protrudes as in the replica template 10′ of the comparativeexample. As a result, in the replica template 10 that is frequentlyused, there is no risk that a structure like the pillar 13′, which haslow mechanical strength, will be damaged and the life of the replicatemplate 10 can be extended.

Furthermore, unlike the replica template 10′ of the comparative examplecomposed of only the convex shape, the replica template 10 includes boththe above-mentioned uneven shape and the height difference on thesurface thereof is relatively small. Therefore, pattern transfer can beperformed without increasing the resist film 240 thickness.

Further, if there is a slight height difference between the pillar 243of the resist pattern 240 p and the other surface of the resist pattern240 p, the pillar 243 can be exposed from the inverted film 250, so thatan aspect ratio of the hole 13 of the replica template 10 can be keptlow, and the height difference on the surface of the replica template 10can be further reduced. The production of such a replica template 10becomes easier.

The replica template 10 enables the manufacturing method of thesemiconductor device 200, and the advantageous effects of themanufacturing method of the semiconductor device 200 of the embodimentdescribed above are thus provided.

According to the master template 20 of the embodiment, the groove 22recessed from the basal plane 21 to a predetermined depth, and thepillar 23 protruding higher than the basal plane 21 from the bottomsurface 22 b of the groove 22 are provided. The master template 20having such a shape enables the production of the replica template 10 ofthe embodiment.

According to the manufacturing method of the master template 20 of theembodiment, the pattern 20 p is formed in two steps: forming theprotrusion 23 p and forming the groove 22. As a result, the pillar 23protruding from the bottom surface 22 b of the groove 22 can be formed.

According to the manufacturing method of the master template 20 of theembodiment, the position where the protrusion 23 p is formed and theposition where the groove 22 is formed are aligned by EB drawing. As aresult, the groove 22 can be aligned with respect to the position of thepillar 23 with high accuracy.

According to the manufacturing method of the master template 20 of theembodiment, the material to be sputtered, which becomes the HM pattern50 p, when forming the groove 22 is formed on the entire surface of thebase material 20 b in a state where the pillar 33 of the HM film 30 isleft in the protrusion 23 p. As a result, the pillars 33 and 53 on theprotrusion 23 p can be made thicker than the HM film 50 on the basalplane 21 of the base material 20 b. Therefore, when the HM film 50 isopened to form the groove 22, at least the pillar 33 can be left on theprotrusion 23 p. Since the pillar 33 protects the protrusion 23 p whenthe groove 22 is formed, the height of the protrusion 23 p can bemaintained, and thus an aspect ratio of the pillar 23 can be maintained.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of thedisclosure. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the disclosure.

What is claimed is:
 1. A method of manufacturing a semiconductor device,the method comprising: forming a first film on a substrate; forming asecond film on the first film; placing an imprint resist on the secondfilm; pressing an imprint template against the imprint resist totransfer a pattern from the imprint template to the imprint resist, thepattern of the imprint template including: a step portion protrudingfrom a first surface to a first height and extending in a firstdirection along the first surface, and a hole in the step portionextending in a second direction into the imprint template and having abottom that is at a level below the first surface in the seconddirection.
 2. The method according to claim 1, further comprising:etching the patterned imprint resist to expose a portion of the secondfilm corresponding to the step portion in the imprint template; andetching the second film using the patterned imprint resist as an etchmask to form a first groove in the second film.
 3. The method accordingto claim 2, further comprising: forming a third film over the patternedimprint resist and the etched second film, the third film havingdifferent etch characteristics from second film and the imprint resist.4. The method according to claim 3, further comprising: etching back aportion of the third film to expose an upper end of a columnar patternportion formed in the patterned imprint resist, the columnar patternportion corresponding the hole of the imprint template; removing thecolumnar portion to form a first hole in the third film; etching thefirst film through the first hole to form a second hole in the firstfilm; removing the third film to expose the first groove in the secondfilm; and etching the first film using the second film as an etch maskto form a second groove corresponding to the first groove above thesecond hole.
 5. The method according to claim 4, further comprising:stripping the second film after forming the second groove.
 6. The methodaccording to claim 4, further comprising: plating a metal into thesecond groove and the second hole.
 7. The method according to claim 1,wherein the substrate includes a transistor formed thereon.
 8. Themethod according to claim 1, wherein the imprint resist is aphotocurable organic resin material.
 9. The method according to claim 8,further comprising: curing the imprint resist with light while pressingthe imprint template against the imprint resist.
 10. The methodaccording to claim 1, wherein the first film is an insulator film. 11.The method according to claim 1, wherein the second film is aspin-on-carbon material.
 12. The method according to claim 1, whereinthe third film is a spin-on-glass material.